Comparison of sedation quality and safety of detomidine and romifidine as a continuous rate infusion for standing elective laparoscopic ovariectomy in mares.

OBJECTIVE: To compare efficacy and safety of a continuous rate infusion of detomidine hydrochloride and romifidine hydrochloride for standing elective bilateral laparoscopic ovariectomy in mares. STUDY DESIGN: Blinded, randomized prospective clinical study. ANIMALS: Eighteen healthy mares presenting for elective bilateral ovariectomy METHODS: Mares were randomly assigned to one of two sedation protocols. Prior to surgery, baseline head height, heart rate, respiratory rate, and postural sway were recorded. An IV loading dose of α2-agonist (46 µg/kg romifidine or 13.9 µg/kg detomidine) was administered. Standing sedation was maintained with a continuous rate infusion of the respective α2-agonist (126 µg/kg/h romifidine or 37.8 µg/kg/h detomidine). Intraoperative measurements included respiratory rate, heart rate, head height, postural sway, and response to surgical stimulus. Postoperatively, fecal output was recorded, and pain scoring was performed using composite pain score and visual analog scales. RESULTS: Three of 18 horses required additional α-2 agonists: one detomidine and two romifidine and butorphanol. Head height during surgery was lower (p < .001) in mares receiving detomidine. Postural sway around the vertical axis was greater in mares sedated with detomidine rather than romifidine (p = .013). No differences were detected in intraoperative heart rate, postoperative pain scores or postoperative fecal output between sedation techniques. CONCLUSION: Comparable scores for surgical stimulation and sedation were measured in both sedation groups. No differences in postoperative analgesia or manure production were identified. CLINICAL SIGNIFICANCE: Romifidine appears suitable as an alternative to detomidine and may limit ataxia and head drop in sedated horses.

Comparison of 3 suture closure techniques for pelvic flexure enterotomy in equine cadaveric large colon.

OBJECTIVE: To compare a 2-layer closure with suture line reversal for a pelvic flexure enterotomy to 1-layer and traditional 2-layer hand sewn closures. STUDY DESIGN: Ex vivo, simple randomized study. SAMPLE POPULATION: Large colon segments from adult horses (n = 18). METHODS: Pelvic flexures were harvested from 18 horses and randomly assigned to 1 of 3 closure techniques (n = 6 per technique). A 10-cm enterotomy was made in each pelvic flexure and closed with the assigned technique. Closure time, luminal diameter via contrast radiographs, and bursting pressure were recorded for each specimen and compared between techniques using 1-way ANOVA with Duncan post hoc test at P < .05. RESULTS: There was a significant difference in closure time (P = .034) with 1-layer closure faster than both the traditional 2-layer closure (P=.024) and the 2-layer closure with suture line reversal (P = .030). There was no significant difference in luminal diameter or bursting pressure between the 3 closure techniques. CONCLUSIONS: Two-layer closure with suture line reversal may be an alternative to traditional 2-layer closure for closure of the pelvic flexure based on ex vivo bursting pressure testing and closure time. A 1-layer simple continuous closure resisted bursting pressure not different to both 2-layer closure techniques. Further in vivo evaluation may be indicated.

The Effects of Mepivacaine Hydrochloride on Antimicrobial Activity and Mechanical Nociceptive Threshold During Amikacin Sulfate Regional Limb Perfusion in the Horse.

OBJECTIVE: To determine the effect of intravenous regional limb perfusion (IVRLP) with a combination of mepivacaine hydrochloride and amikacin sulfate on synovial fluid amikacin sulfate concentration, antimicrobial activity, and mechanical nociceptive threshold (MNT). STUDY DESIGN: Experimental study. ANIMALS: Healthy adult horses (n=9). METHODS: One IVRLP treatment was randomly administered by cephalic vein of each limb: amikacin alone (1 g amikacin in 60 mL saline) or amikacin with mepivacaine (1 g amikacin and 500 mg mepivacaine in 60 mL saline). Opposite treatments were repeated after a 24 hour wash-out period. Amikacin concentration and antimicrobial activity were determined for synovial fluid from middle carpal joints at tourniquet removal and 30 minutes following. Zone of inhibition was determined for Staphylococcus aureus and Escherichia coli. MNT was determined at 3 dorsal metacarpal locations prior to and after sedation, after Esmarch tourniquet application, and 30 minutes after IVRLP prior to and after tourniquet removal. RESULTS: Two limbs from each treatment group were removed because of undetectable amikacin concentrations for a total of 14 data sets analyzed. Synovial fluid amikacin concentrations and zone of inhibition were not significantly different between treatments at any time point. MNT were significantly increased 30 minutes after IVRLP prior to and following tourniquet removal using amikacin and mepivacaine (median, range; 40.0 µg/mL, 38.7-40.0 and 40.0, 25.8-40.0, respectively) compared to amikacin alone (19.5 µg/mL, 18.7-25.6 and 15.3, 13.2-20.5, respectively). CONCLUSION: Addition of mepivacaine to amikacin for IVRLP in the horse as a means of providing analgesia without decreasing antimicrobial activity.

Dose effect and duration of action of liposomal bupivacaine administered as a perineural analgesic in a reversible and adjustable frog-pressure model of equine lameness.

OBJECTIVE: To determine the dose effect of peri-neural liposomal bupivacaine (LB) in an induced forelimb lameness model. ANIMALS: 12 clinically normal adult horses. METHODS: A randomized cross-over design was performed with 1 limb receiving saline and the other LB: low dose (6), high dose (6). Lameness was induced in 1 forelimb using a frog-pressure model. In the lame limb, peri-neural injection of the palmar nerves at the proximal sesamoid bones was performed using saline, low dose LB (0.25 mg/kg) (LDLB), or high dose LB (0.5mg/kg) (HDLB) in random order with a 1-week washout period between treatments. Distal limb swelling, mechanical nociceptive thresholds (MNT), and objective lameness data were collected before and up to 72 hours after peri-neural anesthesia. Data analysis was performed with mixed model ANOVA, equality of medians test, and Kaplan Meier survival analysis. RESULTS: Compared with baseline, horses treated with LDLB and HDLB had improvements in MNT and lameness (P < .001). In the LDLB group, the median duration of analgesia was 4.5 hours (range = 3-6 hours) and the median return to lameness was 7 hours (range = 4-24 hours). In the HDLB group, the median duration of analgesia was 12 hours (range = 4-48 hours) and the median return to lameness was 9 hours (range = 3-48 hours). Mild to moderate swelling was identified in 11/12 (92%) LB limbs. CLINICAL RELEVANCE: Both LDLB and HDLB resulted in loss of skin sensation and improvement of lameness. There was high variability among horses in duration of action for both doses.

Effect of age at training initiation on hoof morphology and lameness in juvenile American Quarter Horses.

BACKGROUND: Lameness, discipline, training intensity, environmental variability, and shoeing are all factors demonstrated to affect hoof loading and therefore act as adaptive stimuli to alter hoof morphology. OBJECTIVES: To evaluate the effect of age at training initiation on hoof morphology and lameness incidence and determine if specific hoof morphology measurements correlate with lameness in juvenile American Quarter Horses. STUDY DESIGN: Prospective cohort study. METHODS: American Quarter Horses (n = 42; 29 two-year-olds, 13 three-year-olds) entering training were monitored for hoof morphology and lameness over 6 months (months 0, 2, 4, and 6). Hoof measurements (palmar/plantar angles, frog base width/length, toe length/angle, heel length/angle, heel and foot width, wall height/angle) from radiographs and photographs were recorded. Lameness was graded subjectively and objectively (Lameness locator®). Statistical analyses were performed with Fisher's exact test and repeated measures ANOVA with p < 0.05. RESULTS: 25/42 horses developed subclinical lameness (16/42 forelimb, 19/42 hindlimb), with 3-year-olds developing lameness more frequently compared to 2-year-olds overall (p = 0.04; 84.6 vs. 48.3%) and in forelimbs (p = 0.05; 61.5% vs. 27.6%); no difference was noted between 2- versus 3-year-olds in hindlimbs (p = 0.2; 61.5% vs. 37.9%). In lame versus sound forelimbs, 3-year-olds had decreased foot width (p = 0.03; 11.48 cm [CI 10.68-12.28] vs. 12.21 cm [CI 11.99-12.42]), decreased toe length (p = 0.03; 6.02 cm [CI 5.69-6.36] vs. 6.45 cm [CI 6.32-6.58]), shorter lateral wall height (p = 0.03; 4.64 cm [CI 4.31-4.96] vs. 5.11 cm [CI 5.03-5.2]), and shorter medial wall height (p = 0.02; 4.58 cm [CI 4.06-5.10] vs. 5.15 cm [CI 4.99-5.30]). In lame versus sound hindlimbs, horses overall (p = 0.05; 3.74, CI 3.53-3.96 vs. 3.55, CI 3.48-3.61) and 3-year-olds had longer heels p = 0.01; 3.90 cm (CI 3.5-4.3) vs. 3.50 cm (CI 3.39-3.61). MAIN LIMITATIONS: Small sample size, lack of control group not entering training. CONCLUSIONS: Three-year-old American Quarter Horses entering training were more likely to develop forelimb lameness than 2-year-olds. This subclinical lameness was associated with specific hoof morphology characteristics (decreased foot width, toe length, heel length, and lateral/medial wall height; greater toe angle).

INTRODUCTION/CONTEXTE: Les boiterie, discipline, intensité d'entraînement, variabilité environnementale et ferrage ont tous été établis comme facteurs affectant le port de poids au niveau du sabot. Ils contribuent aux stimuli adaptatifs qui peuvent altérer la morphologie du sabot. OBJECTIFS: Évaluer l'effet de l'âge en début d'entraînement sur la morphologie du sabot, l'incidence de boiterie et déterminer si des mesures spécifiques de morphologie du sabot pourraient être corrélées avec une boiterie chez les chevaux Quarter Horse Américains. TYPE D'ÉTUDE: Étude de cohorte prospective. MÉTHODES: Des Quarter Horse Américains (n = 42; 29 2 ans, 13 3 ans) en début d'entraînement ont été suivi pour la présence de boiterie et la conformation de leur sabot sur une période de 6 mois (mois 0, 2, 4, 6). Des mesures de sabot (angles palmaires/plantaires, largeur/longueur de la base de la fourchette, longueur/angle de la pince, longueur/angle des talons, largeur du pied et des talons, hauteur/angle de la muraille) à partir de radiographies et de photographies ont été recueillies. Les boiteries ont été gradées subjectivement et objectivement (Lameness locator®). Des analyses statistiques ont été effectuées avec la méthode exacte de Fisher et ANOVA pour mesures répétées avec un p < 0.05. RÉSULTATS: 25/42 chevaux ont développé une boiterie sous-clinique (16/42 membre antérieur, 19/42 membre postérieur). Les chevaux âgés de 3 ans ont développé une boiterie de façon plus fréquente comparativement aux 2 ans (p = 0.04; 84.6 vs. 48.3%) et aux membres antérieurs (p = 0.05; 61.5% vs. 27.6%); il n'y avait pas de différence au niveau des membres postérieurs entre les 2 et 3 ans. En comparant les chevaux boiteux des antérieurs avec ceux qui ne boitaient pas, les 3 ans avaient une largeur de sabot diminuée (p = 0.03; 11.48 cm [IC 10.68-12.28] vs. 12.21 cm [IC 11.99-12.42]), une longueur de pince plus courte (p = 0.03; 6.02 cm [IC 5.69-6.36] vs. 6.45 cm [IC 6.32-6.58]), une hauteur de muraille latérale plus courte (p = 0.032; 4.64 cm [IC 4.31-4.96] vs. 5.11 cm [IC 5.03-5.2]) et une hauteur de muraille médiale plus courte également (p = 0.024; 4.58 cm [IC 4.06-5.10] vs. 5.15 cm [IC 4.99-5.30]). En comparant les chevaux boiteux des postérieurs avec ceux qui ne boitaient pas, chevaux dans l'ensemble (p = 0.05; 3.74, CI 3.53-3.96 vs. 3.55, CI 3.48-3.61) et les 3 ans avaient des talons plus long (p = 0.01; 3.90 cm [IC 3.5-4.3] vs. 3.50 cm [IC 3.39-3.61]). LIMITES PRINCIPALES: Petite taille d'échantillon, aucun groupe contrôle n'ayant pas commencé l'entraînement. CONCLUSIONS: Les Quarter Horse Américains âgés de 3 ans qui débutent l'entraînement sont plus à risque de développer une boiterie des antérieurs comparativement aux chevaux de 2 ans. Une boiterie sous-clinique était associée à des caractéristiques morphologiques spécifiques au sabot (Largeur du sabot, longueur de la pince, longueur des talons et hauteur des murailles latérales et médiales toutes diminuées; angle de la pince augmenté).

Hoof Unevenness in Juvenile Quarter Horses During First 6 Months of Training.

The role of hoof morphology is increasingly recognized as a factor associated with lameness incidence in performance horses. The primary objective was to evaluate effect of training initiation on hoof unevenness in Quarter Horses (n = 42; 29 2-year-olds, 13 3-year-olds) over 6-months (m) in training (m0, m2, m4, and m6). Horses were objectively assessed for lameness (inertial sensor system) and photographs and radiographs of feet were taken. Hoof measurements were taken (palmar/plantar angles, frog base width/length, toe length/angle, heel length/angle, heel/foot width, wall height/angle), and analyzed with regards to laterality. Front and hindfoot pairs were determined even if toe angles were within 1.5°. Statistical analyses were performed (Fisher's exact test, mixed-model linear regression, P < .05). There were no differences in distal phalanx palmar/plantar angle between lame/nonlame forelimbs (P = .54) or hindlimbs (P = .20). Unevenness between front feet was seen in toe angle m6 (P < .001), heel length m6 (P = .01) and heel angle over time (P = .006). Unevenness between hind feet was seen at m6 in toe angle (P < .001), heel length (P = .009) and heel angle (P = .02). Lameness incidence did not differ between even and uneven footed horses in forelimbs (P = .64) or hindlimbs (P = .09). In uneven feet, there was no difference in lameness between high versus low foot in forelimbs (P = .34) or hindlimbs (P = .29). Limitations include lack of control group not entering training, lack of consistency in timing data collection to previous trimming, and small sample size. In summary, differences in foot measurements and laterality were noted over time following training initiation in juvenile Western performance horses.

Survey of equine veterinarians regarding primary equine back pain in the United States.

Back pain is a common complaint, clinical finding and performance limiting factor in sport horses. This study sought to gather current veterinary trends in the diagnosis, treatment and management of primary equine back pain in the United States. A 22 question survey was distributed electronically to equine practitioners through AAEP and ACVSMR listservs and through closed social media groups. The survey was open from April 20, 2022 to July 5, 2022. Responses were analyzed using Microsoft excel pivot tables. Ninety-seven survey responses were obtained and analyzed. Respondents reported the clinical signs most frequently relayed to them by the owner/rider/trainer of horses diagnosed with primary back pain were behavioral issues and poor performance. Most common diagnostic tests reported were radiography of the spinous processes, thoraco-lumbar vertebral bodies, and transcutaneous ultrasound of the thoraco-lumbar region. Most common pathologies reported were impinging dorsal spinous processes, degenerative sacro-iliac joint disease, and osteoarthritis in lumbar or thoracic articular process joints. In regards to impinging spinous process ("kissing spine") treatments, 72.2% of respondents recommended surgery only after non-surgical treatments failed, and 14.6% of respondents never recommended surgery. The majority (82%) of respondents reported some level of improvement in clinical signs of primary back pain with rehabilitation alone. To date, there has been no consensus or discussion about common abnormalities, diagnostic tests, treatments or management options for primary equine back pain in the United States. Results of this survey are a starting point showing current trends in diagnosis, treatment and management of primary equine back pain among equine practitioners in the United States showing 82% of practitioners using rehabilitation as a component of treatment.

Liposomal bupivacaine provides longer duration analgesia than bupivacaine hydrochloride in an adjustable sole-pressure model of equine lameness.

OBJECTIVE: To compare the efficacy and duration of action for perineural analgesia with liposomal bupivacaine (LB) versus bupivacaine hydrochloride (BHCl) in a sole-pressure induced model of forelimb lameness in horses. ANIMALS: 6 healthy adult research horses. PROCEDURES: In 1 randomly assigned forelimb, grade 3/5 lameness was induced by use of a sole-pressure lameness model. Objective lameness (vector sum [VS]) was determined with an inertial sensor system at 0, 1, 6, and 24 hours after lameness induction to evaluate the model. Mechanical nociceptive thresholds (MNTs) and objective lameness (VS and force platform kinetics) were recorded prior to and at 1, 6, 24, 48, and 72 hours after perineural anesthesia of the palmar nerves at the level of the proximal sesamoid bones with LB or BHCl in random order, with a 1-week washout period between crossover treatments. Data analysis was performed with mixed-model ANOVA. RESULTS: When evaluating the lameness model, there was a decrease in lameness at 24 hours in at least 1 limb of each horse (7/12 limbs); thus, screw length was increased by 1 to 2 mm at each 24-hour interval to maintain lameness. Compared with results at baseline, horses treated with BHCl had significant improvements in median MNT and VS identified at only 1 hour after injection, whereas treatment with LB yielded significantly improved median MNT, VS score, and peak vertical force for up to 24 hours. DISCUSSION: In this experimental model of forelimb lameness, LB provided longer analgesia when compared with BHCl and should be further investigated for treatment of pain in horses.

Partial carpal arthrodesis in a 2-year-old alpaca.

A 2-year-old alpaca was presented for acute onset right forelimb lameness. Clinical findings included bilateral carpal valgus (more severe in the affected forelimb) and medial instability of the right radio-carpal joint. Surgical treatment consisted of radio-carpal joint arthrodesis, which is presented as a therapeutic option for severe carpal instability secondary to injury to the supporting ligamentous structures of the carpus.

Evaluation of a Commercial Activity Monitor for Determining Step Counts in Horses.

Monitoring activity level has become popular in people and animals. In the horse, these monitors may be helpful for the detection of disease, monitor limb loading after surgery, and assist in rehabilitation. The objective of this study was to evaluate the accuracy of a commercial activity monitor (AM) (FitBit Zip) in horses. In Part 1, four stalled horses had five AMs placed (head, chest, withers, and left forelimb and hindlimbs) with stride length setting of 60.96 cm and were monitored for 24 hours with AM and video. In Part 2, four stalled horses had two AMs placed (left forelimb and hindlimbs) with stride length setting of 30.48 cm and were monitored for 24 hours with AM and video. In Part 3, three horses with two AMs (left forelimb and hindlimbs) had step data collected at the walk and trot in hand by AM and video. AM and video data were compared using Pearson's correlation coefficients and by calculating AM to video step count ratios. In Part 1, there was considerable movement of AMs at the chest and withers, but head and limb mounted AMs were more secure. In Part 2, video and AM activity counts were moderate to high for forelimb and hindlimbs with R2 values of 0.82 and 0.74, respectively. From Part 3, AMs mounted on either forelimb or hindlimbs approximately doubled the step counts compared to the video. While this AM did not accurately count steps, it may be able to provide general information on activity level in the stalled horses.

Polypropylene mesh repair of a unilateral, congenital hernia in the inguinal region in a Thoroughbred filly.

A 2-day-old Thoroughbred intact female was presented for a large subcutaneous swelling in the right inguinal region. Surgical repair was performed using a double layer polypropylene mesh. To the authors' knowledge, there have been no previous reports of surgical repair of congenital body wall hernias with polypropylene mesh in foals.

Surgical Treatment of an Osseous Cyst-Like Lesion in the Middle Phalanx Communicating With the Distal Interphalangeal Joint of a Horse.

Subchondral or osseous cyst-like lesions within the distal aspect of the middle phalanx are not commonly reported in equids. These osseous lesions, which can communicate with the distal interphalangeal joint, can result in significant lameness and may not respond well to medical management. This report describes the clinical, diagnostic imaging, and surgical management of a 4-year-old mixed breed gelding where medical management of a chronic subchondral osseous cyst-like lesion of the middle phalanx, which communicated with the distal interphalangeal joint, was unsuccessful. A successful outcome was accomplished after surgical cyst debridement and packing with tricalcium phosphate, a bone marrow aspirate, and platelet-rich plasma.

Evaluation of the effects of commonly used α2-adrenergic receptor agonists alone and in combination with butorphanol tartrate on objective measurements of lameness in horses.

OBJECTIVE: To determine the effects of 3 α2-adrenergic receptor agonists (α2-ARAs), alone or in combination with butorphanol tartrate, on objective measurements of lameness in horses. ANIMALS: 17 adult polo horses with naturally occurring forelimb or hind limb lameness (or both). PROCEDURES: In a crossover design, each horse received each protocol (saline [0.09% NaCl] solution [2 mL, IV] or xylazine hydrochloride [0.33 mg/kg, IV], detomidine hydrochloride [0.007 mg/kg, IV], or romifidine hydrochloride [0.033 mg/kg, IV] alone or in combination with butorphanol [0.007 mg/kg, IV]) in random order, with a washout period (≥ 7 days) between protocols. Horses were assessed immediately prior to (baseline) and 10, 15, 20, 30, and 40 minutes after administration of each protocol for degree of sedation, mechanical nociceptive threshold (MNT), and objective lameness measurements. RESULTS: Compared with baseline values, sedation scores and MNTs were significantly higher at all evaluated time points following administration of all sedation protocols except xylazine alone; following administration of xylazine alone, sedation scores and MNTs were significantly higher at ≤ 30 minutes and ≤ 20 minutes, respectively. Significant differences in objective forelimb lameness measurements were noted after administration of the 3 α2-ARA-butorphanol combinations. Most significant differences in objective measurements of hind limb lameness were detected after administration of detomidine or romifidine, alone or in combination with butorphanol. CONCLUSIONS AND CLINICAL RELEVANCE: In the study horses, xylazine alone had the least impact on objective lameness measurements. The administration of α2-ARAs, particularly detomidine or romifidine, alone or in combination with butorphanol, resulted in small but significant effects on objective lameness measurements.

Sensor analysis and initial assessment of detectable first hoof contacts and last break-overs as unique signal fluctuations for equine gait analysis.

The objective of the control study was to assess 2 prominent fluctuations in a single optical signal as being either a true first hoof contact or a last break-over based on descriptive measures. The study builds on initial findings from a preliminary investigation of the embedded-optical-base system's (EOBS) capabilities in signal capturing and feasibility as potential alternative to existing gait technologies, such as piezoelectric (e.g., load cell) systems. Hoof contacts and break-overs were measured (0 to 1 au; arbitrary units) using a 2.4-m (length) × 0.9-m (width) platform containing 1 EOBS. Three mixed-breed horses (n = 3) were injected with saline or either 100 IU or 200 IU Botox (i.e., onabotulinumtoxinA) with a 2.5-mL final volume. Injections were made into the deep digital flexor muscle at the motor end plates, with electromyography and ultrasound guidance. Horses were observed for 3 time points (pre-, post-, and recovery test days) over the span of a 4-mo period. Signal fluctuations [i.e., amplitude of hoof impacts based on true first hoof contacts (ΔS TS) and true last break-overs (ΔS TL)] and kinematics [i.e., complete gait pass (CGP) time duration (T)] were recorded from each horse. Visual observations and video analysis were used for determining gait pattern categories. Individual horse measurements were analyzed for each trial, compared with video data and classified. Comparison of primary signal fluctuations (i.e., ΔS TS vs. ΔS TL; forelimb vs. hindlimb) exhibited significant differences between hoof contacts and break-overs (P < 0.05). Right and left forelimb hoof contacts and hindlimb break-overs were not significantly different (P = 0.966; 0.063 ± 0.135; Estimate ± SE; P = 0.606; 0.176 ± 0.142; Estimate ± SE, respectively). Additionally, treatment vs. saline forelimbs did not exhibit significant difference (P = 0.7407; -0.098 ± 0.279; Estimate ± SE). Overall, data showed that the EOBS can collect repeatable and unique primary signal fluctuations as prominent and different gait measurements providing evidence to further development and research of the sensing system.

Use of a locking compression plate for equine proximal interphalangeal joint arthrodesis: 29 cases (2008-2014).

OBJECTIVE To describe clinical use of a locking compression plate (LCP) for proximal interphalangeal joint (PIPJ) arthrodesis in horses and compare outcomes for horses that underwent the procedure as treatment for fracture of the middle phalanx (P2) versus other causes. DESIGN Retrospective case series. ANIMALS 29 client-owned horses. PROCEDURES Medical records of 2 veterinary teaching hospitals from 2008 through 2014 were reviewed to identify horses that underwent PIPJ arthrodesis of 1 limb. Signalment, surgical, and outcome-related variables were recorded. Owners were contacted from 1 to 6 years after surgery to determine rehabilitation time, current use of the horse, and overall owner satisfaction with the procedure. Success was determined on the basis of owner satisfaction and outcome for intended use. Variables of interest were compared statistically between horses that underwent surgery for P2 fracture versus other reasons. RESULTS 14 horses underwent surgery for treatment of P2 fracture, and 15 had surgery because of osteoarthritis, subluxation, or osteochondrosis. Median convalescent time after surgery (with no riding or unrestricted exercise) was 7 months. Four horses were euthanized; of 23 known alive at follow-up, 22 were not lame, and 18 had returned to their intended use (8 and 10 at higher and lower owner-reported levels of work, respectively). Horses undergoing arthrodesis for reasons other than fracture were significantly more likely to return to their previous level of work. Twenty-two of 24 owners contacted indicated satisfaction with the procedure. CONCLUSIONS AND CLINICAL RELEVANCE Surgical arthrodesis of the PIPJ was successful in most horses of the study population. Various nuances of the system for fracture repair need to be understood prior to its use.

Comparison of the diagnosis and management of unilaterally castrated and cryptorchid horses at a referral hospital: 60 cases (2002-2006).

OBJECTIVE: To determine the incidence of unilaterally castrated horses among horses admitted to the hospital for castration and to compare horses that underwent previous unilateral castration with horses that had cryptorchism. DESIGN: Retrospective case series. ANIMALS: 16 unilaterally castrated horses and 44 cryptorchid horses. PROCEDURES: Medical records of horses that were admitted to the veterinary medical teaching hospital for castration, including cryptorchid and unilaterally castrated horses, between January 2002 and December 2006 were reviewed. Medical records of unilaterally castrated horses and cryptorchid horses were examined for age, breed, history, diagnostic procedures, surgical technique of cryptorchidectomy, location of the retained testicle, and cost of surgery. RESULTS: Of 160 horses admitted for castration, 16 (10%) had undergone previous unilateral castration and 44 (27.5%) had cryptorchidism. Unilaterally castrated horses were significantly older than cryptorchid horses. No significant difference was found in left versus right distribution of testicles. No significant difference was found in abdominal versus inguinal distribution of left-sided testicles. Unilaterally castrated horses had a significantly lower proportion of right inguinal testicles, compared with cryptorchid horses. The cost of diagnosis and management of unilaterally castrated horses was significantly greater than in cryptorchid horses. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the distribution of retained testicles is significantly different in unilaterally castrated horses, compared with cryptorchid horses, which may affect the selection of diagnostic and surgical approaches to unilaterally castrated horses.

Persistent dorsal displacement of the soft palate attributable to a frenulum of the epiglottis in a racing Thoroughbred.

CASE DESCRIPTION: A 7-year-old sexually intact male Thoroughbred racehorse was evaluated because of exercise intolerance, respiratory tract noise, and coughing when eating. CLINICAL FINDINGS: A persistent dorsal displacement of the soft palate was identified during endoscopic examination of the upper portions of the respiratory tract. Radiography of the pharyngeal and laryngeal regions revealed a hypoplastic epiglottis that was ventral to, and not in contact with, the soft palate. The horse was anesthetized, and an oral endoscopic examination revealed a subepiglottic frenulum that had resulted in the dorsal displacement of the soft palate. TREATMENT AND OUTCOME: The frenulum was transected transendoscopically by use of a diode laser. Twenty-four hours following surgery, repeat endoscopic and radiographic examinations revealed that the epiglottis had returned to its correct anatomic position in relation to the soft palate. Four weeks after surgery, endoscopy of the upper portions of the airway revealed recurrence of the dorsal displacement of the soft palate. CLINICAL RELEVANCE: A subepiglottic frenulum should be considered as a cause of persistent dorsal displacement of the soft palate in horses. An endoscopic examination of the oropharyngeal region should be performed in horses prior to undertaking any surgical interventions to treat persistent dorsal displacement of the soft palate.

Evaluation of a portable media device for use in determining postural stability in standing horses.

OBJECTIVE To determine the ability of an accelerometer within a commercially available portable media device (PMD) to measure changes in postural stability of standing horses during various stance conditions and to compare these results with data obtained by use of a stationary force platform. ANIMALS 7 clinically normal horses. PROCEDURES A PMD was mounted on a surcingle; the surcingle was placed immediately caudal to the highest point of the shoulders (withers). Each horse was examined while standing on a stationary force platform system in a normal square stance, forelimb base-narrow stance, and normal square stance at 5 and 10 minutes after sedation induced by IV administration of xylazine hydrochloride. A minimum of 5 trials were conducted for each stance condition. Ranges of craniocaudal and mediolateral motion as well as SDs were collected for the PMD and force platform system. Analyses were performed with mixed-model ANOVAs, and correlation coefficients were calculated. RESULTS Stance condition significantly altered craniocaudal accelerations measured by use of the PMD, all craniocaudal and mediolateral displacements of the center of pressure, and velocities measured by use of the stationary force platform. For both the PMD and force platform, SDs were significantly affected by stance condition in both craniocaudal and mediolateral directions. Correlation coefficients between the systems for all variables were low to moderate (r = 0.18 to 0.58). CONCLUSIONS AND CLINICAL RELEVANCE Body-mounted PMDs should be investigated for use in assessment of postural stability in horses with neuromuscular abnormalities.

Effects of sensor position on kinematic data obtained with an inertial sensor system during gait analysis of trotting horses.

OBJECTIVE To determine the effects of altering location of right forelimb and pelvic sensors on kinematic data obtained with a commonly used inertial sensor system during gait analysis of trotting horses. DESIGN Experimental study. ANIMALS 12 horses with mild to moderate lameness of at least 1 hind limb, with or without lameness of the forelimbs. PROCEDURES All horses were examined while trotting on a high-speed treadmill. The right forelimb sensor was tested at 3 anatomic locations in random order: dorsal midline and 2 cm medial and lateral to that midline. During another treadmill session, the pelvic sensor was tested at 5 anatomic locations in random order: dorsal midline, 2 cm to the right and left of midline, and 2 cm cranial and caudal to the tubera sacrale on the midline. Laterality of the pelvic sensor was analyzed in 2 ways: sensor toward the right or left and sensor toward or away from the lame or lamest hind limb. Maximum and minimum differences in head and pelvic motion and vector sum values were ranked and compared with values for the midline location by means of mixed-model ANOVA. RESULTS Altering the location of the right forelimb sensor by 2 cm medially or laterally had no significant effect on forelimb or hind limb kinematics. However, location of the pelvic sensor had a significant effect on minimum difference in pelvic motion, regardless of whether the data were analyzed by laterality (right vs left) or toward versus away from the lame hind limb. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study indicated that a 2-cm change in the location of the pelvic sensor during kinematic gait analysis had a significant effect on hind limb kinematic data of the system used. Therefore, placement of this sensor needs to be anatomically accurate.